/*-
 * Public platform independent Near Field Communication (NFC) library examples
 * 
 * Copyright (C) 2010, Romuald Conty
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *  1) Redistributions of source code must retain the above copyright notice,
 *  this list of conditions and the following disclaimer. 
 *  2 )Redistributions in binary form must reproduce the above copyright
 *  notice, this list of conditions and the following disclaimer in the
 *  documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Note that this license only applies on the examples, NFC library itself is under LGPL
 *
 */

/* Emulates a simple tag */

/* Note that depending on the device (initiator) you'll use against, this
 * emulator it might work or not. Some readers are very strict on
 * responses timings, e.g. a Nokia NFC and will drop communication too
 * soon for us.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <signal.h>

#include <host/nfc.h>

#include "nfc-utils.h"

#define MAX_FRAME_LEN			(264)
#define SAK_ISO14443_4_COMPLIANT	0x20

static byte_t abtRx[MAX_FRAME_LEN];
static size_t szRx = sizeof(abtRx);
static nfc_device_t *pnd;
static bool quiet_output = false;
static bool init_mfc_auth = false;

void intr_hdlr(void)
{
	printf("\nQuitting...\n");
	if (pnd != NULL) {
		nfc_disconnect(pnd);
	}
	exit(EXIT_FAILURE);
}

bool target_io(nfc_target_t *pnt,
	       const byte_t *pbtInput, const size_t szInput,
	       byte_t *pbtOutput, size_t *pszOutput)
{
	bool loop = true;

	*pszOutput = 0;
	
	/* Show transmitted command */
	if (!quiet_output) {
		printf("    In: ");
		print_hex(pbtInput, szInput);
	}
	if (szInput) {
		switch (pbtInput[0]) {
		case 0x30:
			/* Mifare read */
			/* block address is in pbtInput[1] */
			*pszOutput = 15;
			strcpy((char*)pbtOutput, "You read block ");
			pbtOutput[15] = pbtInput[1];
			break;
		case 0x50:
			/* HLTA (ISO14443-3) */
			if (!quiet_output) {
				printf("Initiator HLTA me. Bye!\n");
			}
			loop = false;
			break;
		case 0x60:
			/* Mifare authA */
		case 0x61:
			/* Mifare authB */
			/* Let's give back a very random nonce... */
			*pszOutput = 2;
			pbtOutput[0] = 0x12;
			pbtOutput[1] = 0x34;
			/* Next commands will be without CRC */
			init_mfc_auth = true;
			break;
		case 0xe0:
			/* RATS (ISO14443-4) */
			/* Send ATS */
			*pszOutput = pnt->nti.nai.szAtsLen + 1;
			pbtOutput[0] = pnt->nti.nai.szAtsLen + 1; // ISO14443-4 says that ATS contains ATS_Lenght as first byte
			if (pnt->nti.nai.szAtsLen) {
				memcpy(pbtOutput+1, pnt->nti.nai.abtAts, pnt->nti.nai.szAtsLen);
			}
			break;
		case 0xc2:
			/* S-block DESELECT */
			if (!quiet_output) {
				printf("Initiator DESELECT me. Bye!\n");
			}
			loop = false;
			break;
		default:
			/* Unknown */
			if (!quiet_output) {
				printf("Unknown frame, emulated target abort.\n");
			}
			loop = false;
		}
	}
	/* Show transmitted command */
	if ((!quiet_output) && *pszOutput) {
		printf("    Out: ");
		print_hex(pbtOutput, *pszOutput);
	}

	return loop;
}

bool nfc_target_emulate_tag(nfc_device_t *pnd,
			    nfc_target_t *pnt)
{
	size_t szTx;
	byte_t abtTx[MAX_FRAME_LEN];
	bool loop = true;
	
	if (!nfc_target_init(pnd, pnt, abtRx, &szRx)) {
		nfc_perror(pnd, "nfc_target_init");
		return false;
	}
	
	while (loop) {
		loop = target_io(pnt, abtRx, szRx, abtTx, &szTx);
		if (szTx) {
			if (!nfc_target_send_bytes(pnd, abtTx, szTx, NULL)) {
				nfc_perror(pnd, "nfc_target_send_bytes");
				return false;
			}
		}
		if (loop) {
			if (init_mfc_auth) {
				nfc_configure(pnd, NDO_HANDLE_CRC, false);
				init_mfc_auth = false;
			}
			if (!nfc_target_receive_bytes(pnd, abtRx, &szRx, NULL)) {
				nfc_perror(pnd, "nfc_target_receive_bytes");
				return false;
			}
		}
	}
	return true;
}

int main(int argc, char *argv[])
{
	const char *acLibnfcVersion;
	/* Example of a Mifare Classic Mini
	 * Note that crypto1 is not implemented in this example
	 */
	nfc_iso14443a_info_t nai = {
		{ 0x00, 0x04 },
		0x09,
		4,
		{ 0x08, 0xab, 0xcd, 0xef },
		0,
	};
#if 0
	/* Example of a ISO14443-4 (DESfire) */
	nfc_iso14443a_info_t nai = {
		{ 0x03, 0x44 },
		0x20,
		4,
		{ 0x08, 0xab, 0xcd, 0xef },
		5,
		{ 0x75, 0x77, 0x81, 0x02, 0x80 },
	}
	/* Example of a FeliCa */
	nfc_felica_info_t nfi = {
		0,
		0,
		{ 0x01, 0xFE, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xFF },
		{ 0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xFF },
		{ 0xFF, 0xFF },
	}
#endif
	nfc_target_t nt;

	(void) argc;

#ifdef WIN32
	signal(SIGINT, (void (__cdecl *)(int))intr_hdlr);
#else
	signal(SIGINT, (void (*)(void))intr_hdlr);
#endif
	
	/* Try to open the NFC reader */
	pnd = nfc_connect(NULL);
	
	/* Display libnfc version */
	acLibnfcVersion = nfc_version();
	printf("%s uses libnfc %s\n", argv[0], acLibnfcVersion);
	
	if (pnd == NULL) {
		ERR("Unable to connect to NFC device");
		exit (EXIT_FAILURE);
	}
	
	printf ("Connected to NFC device: %s\n", pnd->acName);
	
	/* Notes for ISO14443-A emulated tags:
	 * * Only short UIDs are supported
	 *   If your UID is longer it will be truncated
	 *   Therefore e.g. an UltraLight can only have short UID, which
	 *   is typically badly handled by readers who still try to send
	 *   their "0x95".
	 * * First byte of UID will be masked by 0x08 by the PN53x
	 *   firmware as security countermeasure against real UID
	 *   emulation.
	 */
	nt.nm.nmt = NMT_ISO14443A;
	nt.nm.nbr = NBR_UNDEFINED;
	memcpy(&nt.nti.nai, &nai, sizeof (nai));
#if 0
	/* Filica */
	nt.nm.nmt = NMT_FELICA;
	nt.nm.nbr = NBR_UNDEFINED;
	/* Example of a ISO14443-4 (DESfire) */
	nt.nm.nmt = NMT_ISO14443A;
	nt.nm.nbr = NBR_UNDEFINED;
#endif
	
	printf("%s will emulate this ISO14443-A tag:\n", argv[0]);
	print_nfc_iso14443a_info(nt.nti.nai, true);
	
	/* Switch off NDO_EASY_FRAMING if target is not ISO14443-4 */
	nfc_configure(pnd, NDO_EASY_FRAMING,
		      (nt.nti.nai.btSak & SAK_ISO14443_4_COMPLIANT));
	printf("NFC device (configured as target) is now emulating the tag, please touch it with a second NFC device (initiator)\n");
	if (!nfc_target_emulate_tag(pnd, &nt)) {
		nfc_perror(pnd, "nfc_target_emulate_tag");
		exit(EXIT_FAILURE);
	}
	
	nfc_disconnect(pnd);
	exit(EXIT_SUCCESS);
}

